Tone activated alert receivers are well known and are regularly used by emergency agencies including fire, police, ambulance, and rescue services. The National Weather Service (NWS) transmits an alert signal to activate commonly available weather alert receivers to warn of impending severe and potentially life threatening weather such as tornadoes, thunderstorms, floods, and blizzards. Known receivers can be set to issue a siren, flash an LED, and/or announce the voice weather alert message in response to receiving and decoding an alert signal.
The NWS and emergency agencies broadcast a digital code as a header preceding each alert message. This digital header usually contains the type of warning, the effective time and expiration time of the warning and the areas effected. Although the type of the warning can be obtained through decoding the header, it has been found that most of the effected public doesn't feel a compelling need for all of the information contained in the alert message, or even all the information contained in just the header. What the public wants is an alert of an impending severe weather condition, such as a tornado, that is specifically directed to them, in sufficient time to take evasive action.
Such warnings are often extremely time critical. Warnings must automatically be received by the ultimate end user, preferably on a dedicated system that will not be interfered with by other communications channels.
U.S. Pat. No. 5,681,852 to Gropper describes a capable system which provides an alert receiver interface. The receiver automatically detects the issuance of an emergency message broadcast on a radio channel, or on another communication system. The system records that alert message into the receiver with an audible day and time stamp for later playback. The system also provides an interface between the alert receiver and other communications systems, including paging system, whereby an alert message, or an alarm tone, is automatically relayed and repeated on the other communication system. The system also teaches selectively activating another communication system for only those alert messages of specific concern to users of the other communications system. In that mode, the alert receiver interface can be set by a user for specific needs such as to detect a fire company's alert signal on a public service radio channel and then go through the recording, day, and time stamp and playback sequences.
While the system described in the '852 is a very capable system, recent tragedies, such as that in Oklahoma City, indicate that a broadly available alert warning system is still badly needed. Such a system should be dedicated to a specific need, without the requirement of being selected by a user. Further, the system should eliminate the mystery of the known complex systems, and be readily acceptable in the market.
Sales figures show that consumers today readily accept pagers and smoke detectors. Consequently, an alert warning system preferably should extend the already widely accepted pager and smoke detector systems to provide an audible early warning of a tornado.